[PATCH] drm/msm/dsi: do not install irq handler before power up the host

[Andrzej Hajda]

W dniu 21.09.2021 o 18:22, Dmitry Baryshkov pisze:
> The DSI host might be left in some state by the bootloader. If this
> state generates an IRQ, it might hang the system by holding the
> interrupt line before the driver sets up the DSI host to the known
> state.
>
> Move the request/free_irq calls into msm_dsi_host_power_on/_off calls,
> so that we can be sure that the interrupt is delivered when the host is
> in the known state.


The established practice is to request IRQ in probe, to avoid 
auto-enabling use IRQF_NO_AUTOEN flag.

Then you can call enable_irq in power-on.


Regards

Andrzej



>
> Fixes: a689554ba6ed ("drm/msm: Initial add DSI connector support")
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> ---
>   drivers/gpu/drm/msm/dsi/dsi_host.c | 21 ++++++++++++---------
>   1 file changed, 12 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index e269df285136..cd842347a6b1 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -1951,15 +1951,6 @@ int msm_dsi_host_modeset_init(struct mipi_dsi_host *host,
>   		return ret;
>   	}
>   
> -	ret = devm_request_irq(&pdev->dev, msm_host->irq,
> -			dsi_host_irq, IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
> -			"dsi_isr", msm_host);
> -	if (ret < 0) {
> -		DRM_DEV_ERROR(&pdev->dev, "failed to request IRQ%u: %d\n",
> -				msm_host->irq, ret);
> -		return ret;
> -	}
> -
>   	msm_host->dev = dev;
>   	ret = cfg_hnd->ops->tx_buf_alloc(msm_host, SZ_4K);
>   	if (ret) {
> @@ -2413,6 +2404,16 @@ int msm_dsi_host_power_on(struct mipi_dsi_host *host,
>   	if (msm_host->disp_en_gpio)
>   		gpiod_set_value(msm_host->disp_en_gpio, 1);
>   
> +	ret = devm_request_irq(&msm_host->pdev->dev, msm_host->irq,
> +			dsi_host_irq, IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
> +			"dsi_isr", msm_host);
> +	if (ret < 0) {
> +		DRM_DEV_ERROR(&msm_host->pdev->dev, "failed to request IRQ%u: %d\n",
> +				msm_host->irq, ret);
> +		return ret;
> +	}
> +
> +
>   	msm_host->power_on = true;
>   	mutex_unlock(&msm_host->dev_mutex);
>   
> @@ -2439,6 +2440,8 @@ int msm_dsi_host_power_off(struct mipi_dsi_host *host)
>   		goto unlock_ret;
>   	}
>   
> +	devm_free_irq(&msm_host->pdev->dev, msm_host->irq, msm_host);
> +
>   	dsi_ctrl_config(msm_host, false, NULL, NULL);
>   
>   	if (msm_host->disp_en_gpio)